Graceful degradation and Progressive Enhancement

Graceful degradation and Progressive enhancement are two different web design strategies

Progressive enhancement

In progressive enhancement you design for bare minimum design standards , generally without any CSS or JavaScript support. In this way webpage will have content that all users can see at least , irrespective of the user agents.

And slowly slowly on the top of baseline design we add on latest standards support for example Latest CSS3 styling.

You can read more about Progressive enhancement at Wikipedia

Graceful degradation

Graceful degradation is very aggressive form of web design in which you are following latest standards and specifications and incase user agent doesn't support them , you don't show latest markup styles. Your webpage just degrades itself to present all what is supported by current user agent.

You can read more about Graceful degradation at Wikipedia

Some of the useful links on the same topic

• The Case for Designing with Progressive Enhancement,” by Todd Parker, Maggie Costello Wachs, Scott Jehl, and Patty Toland (www.peachpit.com/articles/article.aspx?p=1586457)
• “Progressive Enhancement: What It Is, And How To Use It?,” by Sam Dwyer (www.smashingmagazine.com/2009/04/22/progressive-enhancement-what-it-is-and-how-to-use-it)
• “Progressive Enhancement: Paving the Way for Future Web Design,” by Steven Champeon(www.hesketh.com/publications/articles/progressive-enhancement-paving-the-way-for)
• “Graceful degradation versus progressive enhancement,” by Christian Heilman (http://dev.opera.com/articles/view/graceful-degradation-progressive-enhance)

Also please share any other useful link you have for the same.